Automatic safety-loading mechanism for ovens



June 25, 1929. w. c. HUTH AUTOMATIC SAFETY LOADING MECHANISM FOR OVENS 4 Sheets-Sheet 1 Filed Dec. 28, 1927 June 25; 1929.

w. c. HUTH 1,718,861 AUTOMATIC SAFETY LOADING MECHANISM FOR OVENS Filed Dec. 28, 192'? 4 Sheets-Shet 2 3w Z?y' Q:

June 25, 1929. w, HUTH 1,718,861

AUTOMATIC SAFETY LOADING MECHANISM FOR OVENS Filed Dec. 28, 1927 4 Sheets-Sheet 5 June 25, 1929.

w. c. HUTH AUTOMATIC SAFETY LOADING MECHANISM FOR OVENS Filed Dec. 28, 1927 4 Sheets-Sheet 4 5% 1 E 3 R 3 a 1x a 0N x \Y K RY RY f I mm 1 1 111111 \\\1\\1! 1 1 1 v v .u i 9 3 R a 1 Q NM T Q 11 Q g W 3 mm 1 mm 3 R E \Q IIIIIIIIIIIIIII I l atented June 315, 1.329.

UNITED STATES PATENT OFFICE.

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AUTOMATIC SQFETY LOADING MECHANISM FOR OVENS.

Application filed December 28, 1927. Serial No. 243,080.

My invention relates to improved automatic safety loading mechanisms designed with PZLPLHlllEtl' reference for use in conjunction with baking-ovens of the conveyor or moving-hearth type, the object being to produce a reliable loadin mechanism construct ed with particular rererenceto saving time and insuring a high degree of regularity in the placement or delivery of the articles being handled upon the moving hearth. 7

With these ends in view, my invention consists in an automatic safety loading mechanism characterized by a construction and arrangrcment of parts, wherein the resistance to the delivery movement of a pusher-bar automatically stops the timer thereof, whereby the pusher-bar, when such resistance is relieved, is caused to resume and complete its interrupted delivery movement.

My invention further consists in an automatic safety loading mechanism for ovens characterized as above and having certain de' tails of construction and combinations of parts as will be hereinafter described and pointed out in the claims.

in the accompanying drawings:

Fig. 1 is a view in end elevation of an oven equipped with my improved automatic safety loading mechanism;

Fig. 2 is a broken side view thereof;

3 is a broken top or plan view thereof;

F f is an enlarged view in verti a l longitudinal section of one of the telescoping; thrust-links of my improved mechanism, showing, also, the pusher-bar, loading-table, and one of the swinging operating-arms of the mechanism;

Fin. is a corresponding view, showing the parts in the positions due to them when an obstru .:tion prevents the advance of the pusher-oar; and

Fin". 6 is a plan viep v of one of the two switches with its cover removed, also showing schematically the complementary switch, the motor, and the circuit in which both of these switches are interposed.

in carrying out my invention, as herein shown, 1 provide a pusher-bar 10, consisting of an angle iron moving in the horizontal plane and providcd, near its ends, with brackets 11 each mounting a roller 12 traveling upon a track-bar 13 secured to the upper face of the ends of a loading-table or shelf 14, which constitutes the delivery-surface of the oven 15. The inner edge of the said table projects int-o the said oven over the upper reach of the conveyor or movable hearth 1.6, which may be of any approved construction.

Each of the brackets 11 aforesaid is provided with a pair of upstanding arms 17 receiving between them the forward end of the entension-member 1,8 of a telescoping thrustlmk, comprising, also, a tubular-member 19 and a plungerancmber 20. The rear end of the said extension-memher 18 enters the forward end of the tubular-1nember 19 in which it is adj ustably secured by set-screws 21. The said extensioil-member 18, which is pivotally secured to the upstanding arms 17 by means of a pin 22, is formed with a deep clearancebore 23 opening out of its rear end for the clearance of a head 24 at the forward end of a coupling-rod 25, the forward end of which is entered into a bore 26 in the rear end of the said plunger-member and secured in place therein by a pin 27. The rear end of the rod is threaded for the reception of an adjusting-nut 28 for regulating the tension of a helical safety-spring 29 located within the rear end of the tubular-member 19, encircling the rod 25, and interposed between the nut 28 aforesaid and an abutment-ring 31 located within the said tubular-member and secured in place therein by set-scrcws The forward end of the rod 25 passes through and has bearin in the ring 31, with the forward face of which its head 2t is cng ged under normal conditions, as clearly shown in Fig. l.

The rear end of the plmiger-member 20 is entered into the bifurcated lower end of a swinging bowed operating-armSB and pivotally connected therewith by a pin 34. The upper end of the said arm is formed with a hub 35 by means of which it is rigidly attached to one end of an oscillating shaft 36, the ends of which bear in journals secured to the frame 38 of my improved loading mechanism. The complementary thrust-link unit is of corresponding construction, and need. not, therefore, be specifically described, since one description will answer for both.

About midway of its length, the oscillating shaft 36 has secured to it an upstanding rocker-arm 39 having; a slot ll) receiving an adjustable couplingpin 41 which passes through the rear end of a link 42 formed at its forwa rd end with a fork 4L3 embracing and guided by a cam-shaft 44-, and provided with a pin 45 extending laterally into a groove at ilrcne face of a cam l7, which forms the timer of my improved loading-mechanism for the reason that the shape of its groove 16 determines the nature and the speed of the forward and back strokes of the pusher-bar 10, as we'll as the intervals between such strokes.

The cam-shafttl is connected by means of a universal coupling 18 to the low-speed shaft 49 of a reduction-gear mechanism 50 (of any approved type) having its high speed shaft 51 furnished with a gear 52 meshed into by a pinion 53 on the driving-shaft 541 of a variable speed-transmission 55 of the well-known Reeves type. The drive-shaft 56 of the said variable speed-transmission carries a sprocket-wheel'57 connected by a sprocket-chain 58 with a small sprocket-wheel 59 on the shaft 7 ovens of. the conveyor type that the pushbar delivers bread pans or other articles from the shelf to the conveyor when the same is not ready to receir e them, for one reason or another, as, for instance, its tardiness in carrying pans previously delivered upon it forward out of the Way, so as to make room for the oncoming pans. Under these and similar circumstances not necessary to rehearse in detail," but well understood by users of such ovens, jams occur, oftentimes resulting in damage to t-he'mechanism or the pans or bothandalways entailing the loss of valuable time before the jam can be relieved and the trouble removed.

7 To prevent such jams, I provide for stopping the timer-cam by utilizing any untoward resistance to the advance of the pushbar for cutting off the supply of current to the motor, whereby the cam comes to a stop and the forward movement of the pusher-bar is halted.

' With the above end in View, I mount corsaid. The said contact-platcs are respectively engaged for normally closing the circuit between them by the respective lingers 67 of a circuit-closing yoke 68 carried by a bellcrank lever 69, from which it is msulated by a fiber-block 70. The said bell-crank lever is hung upon a pin 71 supported in cars 72 offsetting from the rear end of the housing 63. Normally, the fingers 67 are held in contact with the plates 61 by means of a helical spring 73, the respective ends of which are sleeved over studs 74 and 75 respectively formed upon the housing 63 and the lever 69, as shown in Figs. 4 and 5. The contactplates 61 of the two complementary switches are electrically coupled together in series with each other and with a relay-switch 78 by conductors 76. The relay-switch just mentioned is of ordinary and well-known form and requires no detail illustration or description, other than to say that it is controlled by the current flowing through the conductors 76 and in turn controls the supply of current flowing through the conductor 79 to the motor 61. As shown, a manuallyoperable switch 80 is also interposed in the circuit of the conductors 76 and in series with the automatic switches. Each of the two plunger-members 20 carries an upstanding safety-pin 77 arranged in position to coact with the bell-crank lever 69 for rocking the same to break the circuit, as will hereinafter appear.

In the normal operation of my improved loading-mechanism, the pusher-bar will be moved forward and back by the timer-cam 17 at regular intervals, predicated upon a variety of factors, but chiefly upon the speed of the traveling hearth. When a jam occurs, for whatever reason, the pusher-bar meets with undue resistance to its forward travel. Thereupon the springs 25 of the thrust-links will compress and permit the same to telescope, bringing the safety-pins 77 into eon tact with the bell-crank switch levers 69, whereby the same will be rocked against the tension of their springs 7 4 and the contactyokes 67 lifted away from the contact-plates 64 of the two switches, whereby the circuit to the motor 61 will be broken and the entire loading mechanism stopped, including the cam. This action, while not instantaneous, is so prompt that the forward movement of the pusher-bar is arrested before any danr age can result from the jam, whatever its cause.

Vhen the resistance to the forward movement of the pusher-bar is eased oil. in whatever-manner, the springs 29 will reassert themselves and move the tubular-men]bers 19 and the respective switch-units carried thereby forward, whereby the levers 69 of the two switches will be moved out of engagement with the safety-pins 77, thereby permitting the springs 7 3 to re-closc the circuit through Ill) not been interrupted in such work by the the relay-switch To, which will at once restart the motor 61 and hence the loading mechanism, including the timer-cam 47, which will operate to resume, so to speak, its work of reciprocating the pusher-bar as though it had In other words, the timer-cam, when started,

will move the pusher-bar forward to the limit of its forward stroke and then rearward to the limit of its rearward stroke, though its normal operation had been uninteriaipted.

it will be seen from the foregoing description that, as my improved loading mechanism is constructed and organized, it entirely stops running as a mechanism almost immediately after the occurrence of a jam, on the easing up of which below the power of the springs 529, the same act to close the circuit and restart the cam and hence the mechanisn'i, whereas, in the mechanisms of the prior art, when the pusher-bar was halted by a. am, the remainder of the mechanism continued to go through its regular cycle of movement, with the result that the pusher-bar was not compelled to resume and complete any given forward stroke when the jam eased off. All that was left to chance, since, in the majority of instances, the bar would, after making a partial forward movement and meeting with a jam, after a short interval retire and start a new forward movement. In other words, in the loading mechanisms of the prior art, the cycles of movement of the pusher-bar were mutilated, so to speak, by the occurrences of jams, whereas, in my improved device, the cycles of movement of the pusher-bar are always complete, though in case of ams, delayed.

lily auton'iatically stopping the means employed for reciprocating the pusher-bar itself, the attendant is enabled to do what is nccca sary to release the jam, lmhampercd by the reciprocation of the bar, and without the necessity of performing any manual operations for stopping and starting the bar.

Furthermore, inasmuch as the bar is always carried through its stroke, it can never retire and pick up an additional row of pans and jam them up against a partially-delivcrcd preceding row or pans, as will sometimes happen with the devices of the prior art. l i hen the above contingency hayimens, the initial jam is very much aggravated.

Also, under my improved construction, the skewing of thepans upon the cmivcyor is avoi (led and thci r linear align ment thereupon preserved, which is a highly important factor in uniform baking.

ll claim.

1. The combination with an oven, a movable conveyor located therein, an d a deliverysurface positioned adjacent to the conveyor; of a loading-mechanism for (ilelivering articles from the said surface to the conveyor, comprising a reciprocating pusher-bar, a-

timer therefor, means for driving the timer, and means controlled by the said bar for mu tomatically stopping and starting the said timer; whereby the pushcr-bar is compelled, before it can be retracted, to complete any one of its delivery movements which may have been halted by untoward resistance.

2. The combination with an oven, a movable conveyor locatcd therein, and a deliverysurface positioned adjacent to the conveyor; of a loading-mechanism for delivering the articles from the said surface to the conveyor, comj'irising a reciprocating pusher-bar, a timer-cam therefor, means for driving the timercam, and means controlled by the said bar for automatically stopping and starting the said timer-cam; whereby the pusher-bar is compelled, before it can be retracted, to complete any one of its delivery movements which may have been halted by untoward resistance.

3. The combination with an oven, a movable conveyor located therein, and a deliverysurface positioned adjacent to the conveyor; of a loading-mechanism for delivering articles from the said surface to the conveyor, comprising a reciprocating pusl'ier-bar, a timer therefor, means for driving the said timer, and electrical means brought into operation by variations in the resistance offered by the articles to the delivery movement of the pusher-bar for stopping and starting the said timer; whereby the pusher-bar is compellcd, before it can be retracted, to complete any one of its delivery movcmenits which may have been halted by untoward resistance.

4. The combination with an oven, a movable conveyor located therein, and a deliverysurface positioned adjacent to the conveyor; of a loading-n'icchanism for delivering arti cles from the said surface to the conveyor, comprising a rcci iirocating usbcr-bar, a timer therefor, an electric motor for driving the said timer. and an electric switch interposed in the circuit of the said motor and brought into operation by variations in the resistance offered by the articles to the delivery movement of the bar for starting and stopping the said motor and timer; whereby the pusher-bar is compelled, before it can be retracted, to complete any one of its delivery moven'ionts which may have been halted by untoward resistanc The combination with an even, a movable conveyor located therein, and a deliverysurface positioned. adjacent to the conveyor; of a loading-incchanisin for delivering articles from the said surface to the conveyor, comprising a reciprocating pusher-bar, a ti1ner-cam therefor, an electric motor for driving the said timer-cam, and an electric switch interposed in the circuit of the said motor and brought into operation by variations in the resistance offered by the articles to the delivery movement of the bar for starting and stopping the said motor and timercam; whereby the pusher-bar is compelled, before it can be retracted, to comple-te any I one of its delivery movements which may have been halted by untoward resistance.

6. The combination with an oven, a movable conveyor located therein, and a deliverysurfaee positioned adjacent to the conveyor; of a loading-mechanism for delivering articles from the said surface to. the conveyor, Comprising a reciprocating pusher-bar, a timer-cam therefor, an electric motor for driving the said timer-cam, means for connecting the said timer-cam and the said bar,

said switch to break the circuit to the said' motor; whereby the pusher-bar is con'lpelled, before it can be retracted, to complete any one of its delivery movements which may have been halted by untoward resistance.

In testimony whereof, I have signed this specification.

VVALTER- C. HUTH. 

